This invention relates generally to catheterization systems, and, more particularly, relates to an apparatus and method for performing central venous catheter insertions and exchanges.
The nutritional and fluid balances of hospital patients can be maintained in part or totally using hyperalimentation (total parenteral nutrition) and parenteral fluid and electrolyte solutions. To implement these techniques, an open-ended catheter is positioned with its distal tip in a large vein of a patient's cardiovascular system. Once the tip is positioned in the target vein, the catheter is used to deliver a highly concentrated nutrient solution. The high volume of blood flowing through the vein rapidly dilutes the nutritional solution, thus decreasing the risk of pain, venous inflammation, or thrombosis. Typically, the catheter is positioned to pass through the subclavian or internal jugular vein into the superior vena cava. The same method may be used for delivery of various drugs which cannot be delivered through peripheral veins.
After extended use, catheters can become clogged, bent, suspected of infection, or otherwise inoperative and must be replaced. Following the prior technique of catheter replacement, a guidewire is inserted into the catheter-to-be-removed, the catheter withdrawn, and a replacement catheter slidingly advanced over the guidewire. Unfortunately, this technique of catheter replacement often results in an undesirable irritation of the heart. This irritation results from overinsertion, or overshoot, of the guidewire and/or replacement catheter close to or into the heart.
Several factors contribute to overinsertion of the guidewire. First, the generous lengths of conventional double and triple lumen catheters (35-43 cm) and the accompanying guidewires (60-68.5 cm) often leads to difficulty in accurately estimating the amount of wire inserted Second, during catheter manipulation, both in and out over the guidewire, the wire is frequently moved despite the operator's belief that the wire is being held stationary. Further, in clinical situations the combined goals of maintaining venous access, controlling the free end of the wire, preserving sterility, and sometimes calming a tense patient all compete for the operator's attention, making estimation of wire length and catheter manipulation even more difficult. The results of recent research indicate that sustained and dangerous arrhythmias can result from guidewire stimulation. More particularly, about forty-one percent of guidewire-directed catheter exchanges result in a wide range of atrial arrhythmias. Twenty-five percent of these exchange procedures produce ventricular ectopy, of which thirty percent are ventricular couplets or more malignant ventricular arrhythmias. Research indicates that these arrhythmias often resolve spontaneously with the guidewire still in place or shortly after its withdrawal. Occasionally these arrhythmias continue and may become hemodynamically significant. It is clear that avoidance of overinsertion of the catheter/guidewire assembly is desirable.
In order to avoid such overshoot, and the resulting problems, the placement of catheters might be accomplished while radiographic monitoring is used to track the position of the catheter/guidewire assembly. However, this approach requires increased exposure to radiation, as well as significant additional time and expense.
Accordingly, an object of the invention is to provide an improved method and apparatus for accurately positioning catheters within a vein.
A further object of the invention is to provide an apparatus and method which acts to decrease the chances of cardiac irritation during insertion or exchange of central venous catheters.
These and other objects and features of the invention will be apparent from the following description of the preferred embodiments and from the drawings.